Sexual Reproduction in Flowering Plants | Practice Questions

ByRamakanta Biswal

Here are practice questions for Chapter-2 of Class-XII Biology:- “Sexual Reproduction in Flowering Plants”. These questions are sourced from previous year board question papers, CBSE Sample paper, and NCERT Exemplar.

1 Mark

  1. Write the function of scutellum.
  2. Name the type of flower that favours cross pollination.
  3. Mention the pollinating agent of an inflorescence of a small dull coloured flower with well-exposed stamens and large feathery stigma. Give any one characteristics of pollen grains produced by such flowers.
  4. The following statements seem to describe the water pollinated submerged plants. Which of these statements is/are incorrect?
    1. The flower does not produce nectar.
    2. The pollen grains have a mucilaginous covering.
    3. The brightly coloured female flowers have long stalk to reach the surface.
  5. What is an anatropous ovule?
  6. Write the function of germ pore.
  7. State the function of filliform apparatus found in mature embryo sac of an angiosperm.
  8. Draw a diagram of a matured microspore of an angiosperm. Label its cellular components only.
  9. The pollen of plants like rice and wheat, that normally lose their viability within 30 minutes of dispersal, is available months later plant breeding programs. How?
  10. How could tapetal cell become binucleate?
  11. A bilobed dithecus anther has 50 microspore mother cells per microsporangium. How many male gametophytes can this anther produce?
  12. How do pollen grains of Vasllisneria protect themselves?
  13. The meiocyte of rice has 24 chromosomes. Write the number of chromosomes in its endosperm.
  14. Why do corn cobs have long tessels?
  15. What is the technical term given to ovule?
  16. Why the mitotic divisions in the functional megaspore nucleus are called free-nuclear?

2/3 Marks

  1. What do you understand by monosporic development of female gametophyte?
  2. Mention any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination.
  3. Not all hydrophytes are pollinated by water. Justify by giving two examples of the same.
  4. Both castor and groundnut exhibit double fertilization. But groundnut seeds are non-albuminous while the castor seeds are albuminous. Explain the post fertilization events that are responsible for it.
  5. Are parthenocarpy and apomixis different phenomena? Discuss their benefits.
  6. What do you understand by pollen-pistil interaction? What is its significance?
  7. Mention any two ways by which apomictic seeds get developed.
  8. What is polyembryony? What is its commercial significance?
  9. The generative cell of a two celled pollen divides in the pollen tube, but not in a three-celled pollen. Give reason.
  10. Describe the process of endosperm development in angiosperm.
  11. Write a short note on artificial hybridization.
  12. Differentiate between autogamy, geitonogamy, and xenogamy.
  13. Explain the process of microsporogenesis?

5 Marks

  1. A flower of tomato plant following the process of sexual reproduction produces 240 viable seeds. Answer the following questions giving reason.
    1. What is the minimum number of pollen grains that must have been involved in the pollination of its pistil?
    2. What would have been the minimum number of ovules present in the ovary?
    3. How many megaspore mother cells are involved?
    4. What is the minimum number of microspore mother cells involved in the above case?
    5. How many male gametes were involved in this case?
  2. Give reasons why?
    1. Most zygotes in angiosperms divide only after a certain amount of endosperm is formed.
    2. Micropyle remains as a small pore in the seed coat of a seed.
    3. Integuments of an ovule harden and water content is highly reduced as the seed matures.
    4. Apple and cashew are not called the fruit.
    5. The probability of fruit set in a self-pollinated bi-sexual flower of a plant is far greater than a dioecious plant.
  3. Answer the following:
    1. Plan an experiment and prepare a flow chart of the steps that you would follow to ensure that the seeds are formed only from the desired sets of pollen grains.
    2. Name the type of experiment that you carried out.
    3. What is triple fusion and double fertilization?

 

Important diagram:

  1. Transverse section of a young anther
  2. Enlarged view of one microsporangium showing wall layers (very important)
  3. Mature pollen grain
  4. A typical anatropous ovule (very important)
  5. Stages of development of megaspore mother cell into mature embryo sac
  6. A diagrammatic representation of the mature embryo sac. (very important)
  7. S. of pistil showing path of pollen tube growth (very important)
  8. Fertilized embryo sac showing zygote and PEN
  9. Stages of embryo development in a dicot.
  10. L.S. of an embryo of grass